Question 1

When you increase the volume of a gas, the energy separation between microstates ________

Accepted Answer

A)  increases. 
B)  decreases. 
C)  remains unchanged. 
D)  becomes infinite. 
E)  disappears. 
A)  increases. 
B)  decreases. 
C)  remains unchanged. 
D)  becomes infinite. 
E)  disappears. B

Question 2

Perfect crystals of carbon monoxide (CO) are difficult to prepare because the very small dipole moment allows a few molecules to align in a pattern such as CO OC CO instead of CO CO CO. If such disordered crystals were cooled to 0 K, what would be the value of their absolute entropy?

Accepted Answer

A)  > 0 
B)  = 0 
C)   0, = 0, or  0 or = 0, depending on how carefully it was cooled 
A)  > 0 
B)  = 0 
C)   0, = 0, or  0 or = 0, depending on how carefully it was cooled A

Question 3

Which of the following states of motion have the highest number of occupied excited states at room temperature-rotational, vibrational, or translational?

Accepted Answer

A)  rotational 
B)  vibrational 
C)  translational 
D)  The number of occupied excited states is the same for the three modes of motion. 
E)  None of these, because excited states do not apply to these motions. 
A)  rotational 
B)  vibrational 
C)  translational 
D)  The number of occupied excited states is the same for the three modes of motion. 
E)  None of these, because excited states do not apply to these motions. C

Question 4

Which of the following are true for a reversible process at equilibrium?
I.$\Delta$Suniv = 0
II.$\Delta$Ssys = 0
III.$\Delta$Gsys = 0

Accepted Answer

A)  I only 
B)  II only 
C)  III only 
D)  I and III only 
E)  I, II, and III are all true. 
A)  I only 
B)  II only 
C)  III only 
D)  I and III only 
E)  I, II, and III are all true.

Question 5

A chemist is planning to study a chemical equilibrium for which no measured explicit thermodynamic values are available. However, the reaction involves common chemical species. What information could a chemist use to make predictions about the equilibrium?

Accepted Answer

A)  equilibrium constants for the equilibrium reactions that can be combined to make the new equilibrium 
B)  $\Delta$ $G _ { f } ^ { \circ }$Values for the reactants and products of the new reaction) 
C)  $\Delta$Hf and S° values for the reactants and products of the new reaction) 
D)  All of the above. 
A)  equilibrium constants for the equilibrium reactions that can be combined to make the new equilibrium 
B)  $\Delta$ $G _ { f } ^ { \circ }$Values for the reactants and products of the new reaction) 
C)  $\Delta$Hf and S° values for the reactants and products of the new reaction) 
D)  All of the above.

Question 6

Given the following two measurements of the equilibrium constant for a reaction, calculate $\Delta$H$\degree$ for the reaction.
T, °C K
15 2.6 * 103
25 9.3 * 104

Accepted Answer

A)  255 kJ/mol 
B)  -271 kJ/mol 
C)  3,250 kJ/mol 
D)  -3,250 kJ/mol 
E)  +271 kJ/mol 
A)  255 kJ/mol 
B)  -271 kJ/mol 
C)  3,250 kJ/mol 
D)  -3,250 kJ/mol 
E)  +271 kJ/mol

Question 7

If K for a reaction is large, ________

Accepted Answer

A)  ($\Delta$G$\degree$ is definitely negative.) 
B)  ($\Delta$G$\degree$ is definitely positive.) 
C)  ($\Delta$G$\degree$ is equal to zero.) 
D)  ($\Delta$G is definitely negative.) 
E)  ($\Delta$G is definitely positive.) 
A)  ($\Delta$G$\degree$ is definitely negative.) 
B)  ($\Delta$G$\degree$ is definitely positive.) 
C)  ($\Delta$G$\degree$ is equal to zero.) 
D)  ($\Delta$G is definitely negative.) 
E)  ($\Delta$G is definitely positive.)

Question 8

Which of the listed perturbations would change the value of the equilibrium constant for the following reaction? List those that do as a sequence of letters, for example, ACE.
NH4CO2NH2(s)

Accepted Answer

Question 9

The entropy change of the surroundings, $\Delta$Ssurr, is related to heat transfer, q, with respect to the system and temperature T by ________

Accepted Answer

A)  -q/Tsys = $\Delta$Ssurr. 
B)  +q/Tsys = $\Delta$Ssurr. 
C)  -q/Tsurr = $\Delta$Ssurr. 
D)  q/Tsurr = $\Delta$Ssurr. 
E)  None of these, unless the system undergoes a reversible process. 
A)  -q/Tsys = $\Delta$Ssurr. 
B)  +q/Tsys = $\Delta$Ssurr. 
C)  -q/Tsurr = $\Delta$Ssurr. 
D)  q/Tsurr = $\Delta$Ssurr. 
E)  None of these, unless the system undergoes a reversible process.

Question 10

Alcohols for use as biofuels can be produced from glucose that is obtained from starch and cellulose in plants. For example, 1 mol of glucose can produce 2 mol of ethanol. Use the information in the table below to determine the maximum amount of work and energy that can be produced by the combustion of glucose compared with that by the combustion of 2 mol of ethanol.
C6H12O6(s) $\longrightarrow$ 2CH3CH2OH(l) + 2CO2(g) $$\begin{array} { | c | c | } 
\hline \text { Compound } & \
& \Delta G _ { \mathrm { f } } ^ { \circ } \
& ( \mathbf { k J } / \mathbf { m o l } ) \
\hline \text { Glucose } ( s ) & - 910 \
\hline \text { Ethanol } ( l ) & - 175 \
\hline \text { Water } ( g ) & - 229 \
\hline \text { Carbon dioxide } ( g ) & - 394 \
\hline
\end{array}$$

Accepted Answer

A)  1 mol glucose = 2,830 kJ, 2 mol ethanol = 2,600 kJ 
B)  1 mol glucose = 2,830 kJ, 2 mol ethanol = 1,300 kJ 
C)  1 mol glucose = 2,190 kJ, 2 mol ethanol = 2,780 kJ 
D)  1 mol glucose = 1,420 kJ, 2 mol ethanol = 1,390 kJ 
E)  1 mol glucose = 2,190 kJ, 2 mol ethanol = 1,300 kJ 
A)  1 mol glucose = 2,830 kJ, 2 mol ethanol = 2,600 kJ 
B)  1 mol glucose = 2,830 kJ, 2 mol ethanol = 1,300 kJ 
C)  1 mol glucose = 2,190 kJ, 2 mol ethanol = 2,780 kJ 
D)  1 mol glucose = 1,420 kJ, 2 mol ethanol = 1,390 kJ 
E)  1 mol glucose = 2,190 kJ, 2 mol ethanol = 1,300 kJ

Question 11

Consider a closed container containing a 1 M solution of HCl, above which is air that contains water vapor at its equilibrium vapor pressure. Assume the pressure of the air and water vapor is
1 bar and the temperature of the system is 298 K. Which of the following are in their thermodynamic standard state?
I.The liquid water
II.The HCl solution
III.The water vapor

Accepted Answer

A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
E)  I, II, and III are all in their standard state. 
A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
E)  I, II, and III are all in their standard state.

Question 12

If a reaction A $\rightarrow$ B has $\Delta$ $G _ { rxn } ^ { o }$ > 0, then when the reaction is at equilibrium there will be ________

Accepted Answer

A)  absolutely no B that is formed. 
B)  smaller quantities of B and larger quantities of A. 
C)  equal quantities of A and B. 
D)  large quantities of B and smaller quantities of A. 
E)  absolutely no A remaining. 
A)  absolutely no B that is formed. 
B)  smaller quantities of B and larger quantities of A. 
C)  equal quantities of A and B. 
D)  large quantities of B and smaller quantities of A. 
E)  absolutely no A remaining.

Question 13

Determine the change in the standard entropy of the universe for the reaction
H2(g) + $\frac { 1 } { 2 }$O2(g) $\rightarrow$H2O(g)
Given $ \begin{array}{lll} 
Substance&&S^{\circ}(\mathbf{J} /(\mathbf{m o l} \cdot \mathbf{K}))\
& \Delta H_{\mathbf{f}}^{\circ} & \ & (\mathbf{k J} / \mathbf{m o l}) & \ \mathrm{H}_{2}(g) & & 130.6 \ \mathrm{O}_{2}(g) & & 205.0 \ \mathrm{H}_{2} \mathrm{O}(g) & -241.8 & 188.7\end{array} $

Accepted Answer

A)  -767 J/K 
B)  +197.4 J/K 
C)  -197.4 J/K 
D)  +767 J/K 
E)  +665 J/K 
A)  -767 J/K 
B)  +197.4 J/K 
C)  -197.4 J/K 
D)  +767 J/K 
E)  +665 J/K

Question 14

A sketch of the free energy for a hypothetical chemical equilibrium is shown here. Which sketch shows the equilibrium position labeled with an asterisk (*)?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 15

At what temperature does the Fe(s) $\leftrightarrow$Fe(g) phase transition occur?
$\Delta$H = 415.5 kJ/mol; $\Delta$S = 153.4 J/mol · K.

Accepted Answer

A)  2162°F 
B)  2435°F 
C)  4352°F 
D)  4416°F 
E)  2709°F 
A)  2162°F 
B)  2435°F 
C)  4352°F 
D)  4416°F 
E)  2709°F

Question 16

When a solution of DNA in water is heated, the double helix separates into two single strands. This process is called melting. What can be deduced from this information about the signs of the enthalpy and entropy changes for DNA melting?

Accepted Answer

A) ($\Delta$H > 0 and $\Delta$S > 0) B) ($\Delta$H > 0 and $\Delta$S 0) D) ($\Delta$H < 0 and $\Delta$S < 0) E) This information is not sufficient to determine the signs of $\Delta$H and$\Delta$S. A) ($\Delta$H > 0 and $\Delta$S > 0) B) ($\Delta$H > 0 and $\Delta$S 0) D) ($\Delta$H < 0 and $\Delta$S < 0) E) This information is not sufficient to determine the signs of $\Delta$H and$\Delta$S.

Question 17

Which of the relationships between the free-energy change of a system and associated entropy changes is true?

Accepted Answer

A)  ($\Delta$Gsys = +T $\Delta$Ssystem) 
B)  ($\Delta$Gsys = -T $\Delta$Ssystem) 
C)  ($\Delta$Gsys = +T $\Delta$Suniverse) 
D)  ($\Delta$Gsys = -T $\Delta$Ssurroundings) 
E)  ($\Delta$Gsys = -T $\Delta$Suniverse) 
A)  ($\Delta$Gsys = +T $\Delta$Ssystem) 
B)  ($\Delta$Gsys = -T $\Delta$Ssystem) 
C)  ($\Delta$Gsys = +T $\Delta$Suniverse) 
D)  ($\Delta$Gsys = -T $\Delta$Ssurroundings) 
E)  ($\Delta$Gsys = -T $\Delta$Suniverse)

Question 18

The standard molar entropy of lead(II) bromide (PbBr2) is 161 J/(mol .K). What is the entropy of 2.45 g of PbBr2?

Accepted Answer

A)  +1.07 J/K 
B)  -1.07 J/K 
C)  +161 J/K 
D)  -161 J/K 
E)  0 J/K 
A)  +1.07 J/K 
B)  -1.07 J/K 
C)  +161 J/K 
D)  -161 J/K 
E)  0 J/K

Question 19

Jane can accept that $\Delta$G$\degree$= -RT ln K, but she cannot reconcile the relationship between $\Delta$S$\degree$ and ln K. Please explain it to her.

Accepted Answer

A)  ($\Delta$S$\degree$ = R ln K - $\Delta$H$\degree$/T) 
B)  ($\Delta$S$\degree$ = +ln (K/R) + $\Delta$H$\degree$/T) 
C)  ($\Delta$S$\degree$ = +R ln (K/T) + $\Delta$H$\degree$) 
D)  ($\Delta$S$\degree$= +R ln (K) + $\Delta$H$\degree$/T) 
E)  ($\Delta$S$\degree$ = -R ln (K) + $\Delta$H$\degree$/T) 
A)  ($\Delta$S$\degree$ = R ln K - $\Delta$H$\degree$/T) 
B)  ($\Delta$S$\degree$ = +ln (K/R) + $\Delta$H$\degree$/T) 
C)  ($\Delta$S$\degree$ = +R ln (K/T) + $\Delta$H$\degree$) 
D)  ($\Delta$S$\degree$= +R ln (K) + $\Delta$H$\degree$/T) 
E)  ($\Delta$S$\degree$ = -R ln (K) + $\Delta$H$\degree$/T)

Question 20

One of the following statements A-D may be incorrect. If so, identify it.

Accepted Answer

A)  If both $\Delta$H and $\Delta$S are positive, then a reaction will be spontaneous and produce products only at a sufficiently high temperature. 
B)  If both $\Delta$H and$\Delta$S are negative, then a reaction will be spontaneous and produce products only at a sufficiently low temperature. 
C)  If $\Delta$H > 0 and $\Delta$S  0, then a reaction is spontaneous and will produce products at any temperature. 
E)  All of the statements A-D are correct. 
A)  If both $\Delta$H and $\Delta$S are positive, then a reaction will be spontaneous and produce products only at a sufficiently high temperature. 
B)  If both $\Delta$H and$\Delta$S are negative, then a reaction will be spontaneous and produce products only at a sufficiently low temperature. 
C)  If $\Delta$H > 0 and $\Delta$S  0, then a reaction is spontaneous and will produce products at any temperature. 
E)  All of the statements A-D are correct.

When you increase the volume of a gas, the energy separation between microstates ________

Perfect crystals of carbon monoxide (CO) are difficult to prepare because the very small dipole moment allows a few molecules to align in a pattern such as CO OC CO instead of CO CO CO. If such disordered crystals were cooled to 0 K, what would be the value of their absolute entropy?

Which of the following states of motion have the highest number of occupied excited states at room temperature-rotational, vibrational, or translational?

Which of the following are true for a reversible process at equilibrium? I. $\Delta$ S_univ = 0 II. $\Delta$ S_sys = 0 III. $\Delta$ G_sys = 0

A chemist is planning to study a chemical equilibrium for which no measured explicit thermodynamic values are available. However, the reaction involves common chemical species. What information could a chemist use to make predictions about the equilibrium?

Given the following two measurements of the equilibrium constant for a reaction, calculate $\Delta$ H $\degree$ for the reaction. T, °C K 15 2.6 * 10³ 25 9.3 * 10⁴

If K for a reaction is large, ________

Which of the listed perturbations would change the value of the equilibrium constant for the following reaction? List those that do as a sequence of letters, for example, ACE. NH₄CO₂NH₂(s)

The entropy change of the surroundings, $\Delta$ S_surr, is related to heat transfer, q, with respect to the system and temperature T by ________

If a reaction A $\rightarrow$ B has $\Delta$ $G _ { rxn } ^ { o }$ > 0, then when the reaction is at equilibrium there will be ________

Determine the change in the standard entropy of the universe for the reaction H₂(g) + $\frac { 1 } { 2 }$ O₂(g) $\rightarrow$ H₂O(g) Given Substance (/(\cdot)) \Delta (/) (g) 130.6 (g) 205.0 (g) -241.8 188.7

A sketch of the free energy for a hypothetical chemical equilibrium is shown here. Which sketch shows the equilibrium position labeled with an asterisk (*)?

At what temperature does the Fe(s) $\leftrightarrow$ Fe(g) phase transition occur? $\Delta$ H= 415.5 kJ/mol; $\Delta$ S = 153.4 J/mol · K.

When a solution of DNA in water is heated, the double helix separates into two single strands. This process is called melting. What can be deduced from this information about the signs of the enthalpy and entropy changes for DNA melting?

Which of the relationships between the free-energy change of a system and associated entropy changes is true?

The standard molar entropy of lead(II) bromide (PbBr₂) is 161 J/(mol .K). What is the entropy of 2.45 g of PbBr₂?

Jane can accept that $\Delta$ G $\degree$ = -RT ln K, but she cannot reconcile the relationship between $\Delta$ S $\degree$ and ln K. Please explain it to her.

One of the following statements A-D may be incorrect. If so, identify it.

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: the Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Structures and Applications

Organic Chemistry: Fuels, Pharmaceuticals, Materials, and Life

Chemical Kinetics: Reactions in the Air We Breathe

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acid-Base and Solubility Equilibria: Reactions in Soil and Water

Metal Ions: Colorful and Essential

Electrochemistry: the Quest for Clean Energy

Biochemistry: the Compounds of Life

Nuclear Chemistry: Applications to Energy and Medicine

Life and the Periodic Table

Filters

Exam 18: Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

When you increase the volume of a gas, the energy separation between microstates ________

Perfect crystals of carbon monoxide (CO) are difficult to prepare because the very small dipole moment allows a few molecules to align in a pattern such as CO OC CO instead of CO CO CO. If such disordered crystals were cooled to 0 K, what would be the value of their absolute entropy?

Which of the following states of motion have the highest number of occupied excited states at room temperature-rotational, vibrational, or translational?

Which of the following are true for a reversible process at equilibrium? I. Δ\DeltaΔ Suniv = 0 II. Δ\DeltaΔ Ssys = 0 III. Δ\DeltaΔ Gsys = 0

A chemist is planning to study a chemical equilibrium for which no measured explicit thermodynamic values are available. However, the reaction involves common chemical species. What information could a chemist use to make predictions about the equilibrium?

Given the following two measurements of the equilibrium constant for a reaction, calculate Δ\DeltaΔ H °\degree° for the reaction. T, °C K 15 2.6 * 103 25 9.3 * 104

If K for a reaction is large, ________

Which of the listed perturbations would change the value of the equilibrium constant for the following reaction? List those that do as a sequence of letters, for example, ACE. NH4CO2NH2(s)

The entropy change of the surroundings, Δ\DeltaΔ Ssurr, is related to heat transfer, q, with respect to the system and temperature T by ________

If a reaction A →\rightarrow→ B has Δ\DeltaΔ GrxnoG _ { rxn } ^ { o }Grxno​ > 0, then when the reaction is at equilibrium there will be ________

Determine the change in the standard entropy of the universe for the reaction H2(g) + 12\frac { 1 } { 2 }21​ O2(g) →\rightarrow→ H2O(g) Given Substance (/(\cdot)) \Delta (/) (g) 130.6 (g) 205.0 (g) -241.8 188.7

A sketch of the free energy for a hypothetical chemical equilibrium is shown here. Which sketch shows the equilibrium position labeled with an asterisk (*)?

At what temperature does the Fe(s) ↔\leftrightarrow↔ Fe(g) phase transition occur? Δ\DeltaΔ H = 415.5 kJ/mol; Δ\DeltaΔ S = 153.4 J/mol · K.

When a solution of DNA in water is heated, the double helix separates into two single strands. This process is called melting. What can be deduced from this information about the signs of the enthalpy and entropy changes for DNA melting?

Which of the relationships between the free-energy change of a system and associated entropy changes is true?

The standard molar entropy of lead(II) bromide (PbBr2) is 161 J/(mol .K). What is the entropy of 2.45 g of PbBr2?

Jane can accept that Δ\DeltaΔ G °\degree° = -RT ln K, but she cannot reconcile the relationship between Δ\DeltaΔ S °\degree° and ln K. Please explain it to her.

One of the following statements A-D may be incorrect. If so, identify it.

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: the Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Structures and Applications

Organic Chemistry: Fuels, Pharmaceuticals, Materials, and Life

Chemical Kinetics: Reactions in the Air We Breathe

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acid-Base and Solubility Equilibria: Reactions in Soil and Water

Metal Ions: Colorful and Essential

Electrochemistry: the Quest for Clean Energy

Biochemistry: the Compounds of Life

Nuclear Chemistry: Applications to Energy and Medicine

Life and the Periodic Table

Filters

Which of the following are true for a reversible process at equilibrium? I. $\Delta$ S_univ = 0 II. $\Delta$ S_sys = 0 III. $\Delta$ G_sys = 0

Given the following two measurements of the equilibrium constant for a reaction, calculate $\Delta$ H $\degree$ for the reaction. T, °C K 15 2.6 * 10³ 25 9.3 * 10⁴

Which of the listed perturbations would change the value of the equilibrium constant for the following reaction? List those that do as a sequence of letters, for example, ACE. NH₄CO₂NH₂(s)

The entropy change of the surroundings, $\Delta$ S_surr, is related to heat transfer, q, with respect to the system and temperature T by ________

If a reaction A $\rightarrow$ B has $\Delta$ $G _ { rxn } ^ { o }$ > 0, then when the reaction is at equilibrium there will be ________

Determine the change in the standard entropy of the universe for the reaction H₂(g) + $\frac { 1 } { 2 }$ O₂(g) $\rightarrow$ H₂O(g) Given Substance (/(\cdot)) \Delta (/) (g) 130.6 (g) 205.0 (g) -241.8 188.7

At what temperature does the Fe(s) $\leftrightarrow$ Fe(g) phase transition occur? $\Delta$ H= 415.5 kJ/mol; $\Delta$ S = 153.4 J/mol · K.

The standard molar entropy of lead(II) bromide (PbBr₂) is 161 J/(mol .K). What is the entropy of 2.45 g of PbBr₂?

Jane can accept that $\Delta$ G $\degree$ = -RT ln K, but she cannot reconcile the relationship between $\Delta$ S $\degree$ and ln K. Please explain it to her.